[FFmpeg-user] transcoding mp3 to wav

[jd1008]

On 01/22/2015 10:23 AM, Moritz Barsnick wrote:
> On Thu, Jan 22, 2015 at 10:08:35 -0700, jd1008 wrote:
>> it does the conversion, but does not honour the bitrate param.
>> How do I force the bitrate param for the ourput?
> You didn't show us the output of your ffmpeg command.
>
> Anyway, your approach is wrong. The bitrate of a WAV file is defined by
> its sample format, sample rate, and number of channels (except for
> non-PCM WAV, which is not selected by default).
>
> The default is probably pcm_s16le, which means 16 bits per sample per
> channel. Therefore you can mathematically influence this with "-ac M"
> and "-ar N", or by actually selecting the desired sample format.
>
> Moritz
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Sorry!! I did not know that info was needed. Here it is for track1.
I tried with the params:  -ac 2  -ar 44.1k -ab 1600k   but to no avail.
----------------------------------

ffmpeg version N-51556-ge278500 Copyright (c) 2000-2013 the FFmpeg 
developers
   built on Apr  4 2013 05:11:43 with gcc 4.6 (Debian 4.6.3-1)
   configuration: --prefix=/root/ffmpeg-static/32bit --arch=x86_32 
--extra-cflags='-m32 -I/root/ffmpeg-static/32bit/include -static' 
--extra-ldflags='-m32 -L/root/ffmpeg-static/32bit/lib -static' 
--extra-libs='-lxml2 -lexpat -lfreetype' --enable-static 
--disable-shared --disable-ffserver --disable-doc --enable-bzlib 
--enable-zlib --enable-postproc --enable-runtime-cpudetect 
--enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis 
--enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype 
--enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc 
--enable-libvo-amrwbenc --enable-version3 --enable-libvpx
   libavutil      52. 24.100 / 52. 24.100
   libavcodec     55.  2.100 / 55.  2.100
   libavformat    55.  1.100 / 55.  1.100
   libavdevice    55.  0.100 / 55.  0.100
   libavfilter     3. 49.100 /  3. 49.100
   libswscale      2.  2.100 /  2.  2.100
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  2.100 / 52.  2.100
[mp3 @ 0x98b4700] max_analyze_duration 5000000 reached at 5015510 
microseconds
Input #0, mp3, from 'trak1.mp3':
   Metadata:
     album           : none
     title           : track1
     genre           : instructional
     artist          : me
     track           : 01
     date            : 2014
   Duration: 00:08:54.57, start: 0.000000, bitrate: 321 kb/s
     Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 320 kb/s
     Stream #0:1: Video: mjpeg, yuvj444p, 600x600 [SAR 100:100 DAR 1:1], 
90k tbr, 90k tbn, 90k tbc
     Metadata:
       title           :
       comment         : Cover (front)
Output #0, wav, to 'trak1.wav':
   Metadata:
     IPRD            : trak1
     INAM            : trak1
     IGNR            : Instructional
     IART            : me
     IPRT            : 01
     ICRD            : 2014
     ISFT            : Lavf55.1.100
     Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 
stereo, s16, 1411 kb/s
Stream mapping:
   Stream #0:0 -> #0:0 (mp3 -> pcm_s16le)
Press [q] to stop, [?] for help
size=   15075kB time=00:01:27.53 bitrate=1410.8kbits/s    ^Msize= 
30114kB time=00:02:54.83 bitrate=1411.0kbits/s    ^Msize=   45162kB 
time=00:04:22.19 bitrate=1411.1kbits/s    ^Msize=   60201kB 
time=00:05:49.49 bitrate=1411.1kbits/s    ^Msize=   75245kB 
time=00:07:16.81 bitrate=1411.1kbits/s    ^Msize=   90257kB 
time=00:08:43.96 bitrate=1411.1kbits/s    ^Msize=   92084kB 
time=00:08:54.56 bitrate=1411.1kbits/s    ^M
video:0kB audio:92084kB subtitle:0 global headers:0kB muxing overhead 
0.000320%